[changelog] Changelog for 0.15.12 (#2554)
[changelog] Changelog for 0.15.12 (#2554)

* [changelog] Changelog for 0.15.2

* Add details about tag lifecycle related to carbon ingestion

Co-authored-by: Rob Skillington <7e09c9d3e96378bf549fc283fd6e1e5b7014cc33@chronosphere.io>
m3db/m3db,m3db/m3db,m3db/m3db,m3db/m3db